/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include "tusb.h"

#define ENABLE_DEBUG 0
#include "debug.h"

#if CFG_TUD_MSC

/* whether host does safe-eject */
static bool ejected = false;

/* Some MCU doesn't have enough 8KB SRAM to store the whole disk
 * We will use Flash as read-only disk with board that has
 * CFG_EXAMPLE_MSC_READONLY defined
 */

#define README_CONTENTS \
    "This is tinyusb's MassStorage Class demo.\r\n\r\n" \
    "If you find any bugs or get any questions, feel free to file an\r\n" \
    "issue at github.com/hathach/tinyusb"

enum {
    DISK_BLOCK_NUM  = 16,  /* 8KB is the smallest size that windows allow to mount */
    DISK_BLOCK_SIZE = 512
};

#ifdef CFG_EXAMPLE_MSC_READONLY
const
#endif
uint8_t msc_disk[DISK_BLOCK_NUM][DISK_BLOCK_SIZE] = {
    /*------------- Block0: Boot Sector ------------- *
     * byte_per_sector          = DISK_BLOCK_SIZE;
       fat12_sector_num_16      = DISK_BLOCK_NUM;
     * sector_per_cluster       = 1;
     * reserved_sectors         = 1;
     * fat_num                  = 1;
     * fat12_root_entry_num     = 16;
     * sector_per_fat           = 1;
     * sector_per_track         = 1;
     * head_num                 = 1;
     * hidden_sectors           = 0;
     * drive_number             = 0x80;
     * media_type               = 0xf8;
     * extended_boot_signature  = 0x29;
     * filesystem_type          = "FAT12   ";
     * volume_serial_number     = 0x1234;
     * volume_label             = "TinyUSB MSC";
     * FAT magic code at offset 510-511
     */
    {
        0xEB, 0x3C, 0x90, 0x4D, 0x53, 0x44, 0x4F, 0x53,
        0x35, 0x2E, 0x30, 0x00, 0x02, 0x01, 0x01, 0x00,
        0x01, 0x10, 0x00, 0x10, 0x00, 0xF8, 0x01, 0x00,
        0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0x29, 0x34,
        0x12, 0x00, 0x00, 'T' , 'i' , 'n' , 'y' , 'U' ,
        'S' , 'B' , ' ' , 'M' , 'S' , 'C' , 0x46, 0x41,
        0x54, 0x31, 0x32, 0x20, 0x20, 0x20, 0x00, 0x00,

        /* Zero up to 2 last bytes of FAT magic code */
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xAA
    },

    /* ------------- Block1: FAT12 Table ------------- */
    {
        0xF8, 0xFF, 0xFF, 0xFF, 0x0F  /* first 2 entries must be F8FF,
                                       * third entry is cluster end of readme file */
    },

    /* ------------- Block2: Root Directory ------------- */
    {
        /* first entry is volume label */
        'T' , 'i' , 'n' , 'y' , 'U' , 'S' , 'B' , ' ' ,
        'M' , 'S' , 'C' , 0x08, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4F, 0x6D,
        0x65, 0x43, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        /* second entry is readme file */
        'R' , 'E' , 'A' , 'D' , 'M' , 'E' , ' ' , ' ' ,
        'T' , 'X' , 'T' , 0x20, 0x00, 0xC6, 0x52, 0x6D,
        0x65, 0x43, 0x65, 0x43, 0x00, 0x00, 0x88, 0x6D,
        0x65, 0x43, 0x02, 0x00,
        sizeof(README_CONTENTS)-1, 0x00, 0x00, 0x00  /* readme's files size (4 Bytes) */
    },

    /* ------------- Block3: Readme Content ------------- */
    README_CONTENTS
};

/*
 * Invoked when received SCSI_CMD_INQUIRY
 * Application fill vendor id, product id and revision with string up to 8, 16, 4
 * characters respectively
 */
void tud_msc_inquiry_cb(uint8_t lun, uint8_t vendor_id[8],
                        uint8_t product_id[16], uint8_t product_rev[4])
{
    (void)lun;

    DEBUG("tinyUSB %s\n", __func__);

    const char vid[] = "TinyUSB";
    const char pid[] = "Mass Storage";
    const char rev[] = "1.0";

    memcpy(vendor_id, vid, strlen(vid));
    memcpy(product_id, pid, strlen(pid));
    memcpy(product_rev, rev, strlen(rev));
}

/*
 * Invoked when received Test Unit Ready command.
 * return true allowing host to read/write this LUN e.g SD card inserted
 */
bool tud_msc_test_unit_ready_cb(uint8_t lun)
{
    (void)lun;

    DEBUG("tinyUSB %s\n", __func__);

    /* RAM disk is ready until ejected */
    if (ejected) {
        /* Additional Sense 3A-00 is NOT_FOUND */
        tud_msc_set_sense(lun, SCSI_SENSE_NOT_READY, 0x3a, 0x00);
        return false;
    }

    return true;
}

/*
 * Invoked when received SCSI_CMD_READ_CAPACITY_10 and
 * SCSI_CMD_READ_FORMAT_CAPACITY to determine the disk size
 * Application update block count and block size
 */
void tud_msc_capacity_cb(uint8_t lun, uint32_t* block_count, uint16_t* block_size)
{
    (void)lun;

    DEBUG("tinyUSB %s\n", __func__);

    *block_count = DISK_BLOCK_NUM;
    *block_size = DISK_BLOCK_SIZE;
}

/*
 * Invoked when received Start Stop Unit command
 * - Start = 0 : stopped power mode, if load_eject = 1 : unload disk storage
 * - Start = 1 : active mode, if load_eject = 1 : load disk storage
 */
bool tud_msc_start_stop_cb(uint8_t lun, uint8_t power_condition,
                           bool start, bool load_eject)
{
    (void)lun;
    (void)power_condition;

    DEBUG("tinyUSB %s\n", __func__);

    if (load_eject) {
        if (start) {
            /* load disk storage */
        }
        else {
            /* unload disk storage */
            ejected = true;
        }
    }
    return true;
}

/*
 * Callback invoked when received READ10 command.
 * Copy disk's data to buffer (up to bufsize) and return number of copied bytes.
 */
int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset,
                          void* buffer, uint32_t bufsize)
{
    (void)lun;

    DEBUG("tinyUSB %s\n", __func__);

    /* out of ramdisk */
    if (lba >= DISK_BLOCK_NUM) {
        return -1;
    }

    uint8_t const* addr = msc_disk[lba] + offset;
    memcpy(buffer, addr, bufsize);

    return (int32_t)bufsize;
}

bool tud_msc_is_writable_cb(uint8_t lun)
{
    (void)lun;

    DEBUG("tinyUSB %s\n", __func__);

#ifdef CFG_EXAMPLE_MSC_READONLY
    return false;
#else
    return true;
#endif
}

/*
 * Callback invoked when received WRITE10 command.
 * Process data in buffer to disk's storage and return number of written bytes
 */
int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset,
                           uint8_t* buffer, uint32_t bufsize)
{
    (void)lun;

    DEBUG("tinyUSB %s\n", __func__);

    /* out of ramdisk */
    if (lba >= DISK_BLOCK_NUM) {
        return -1;
    }

#ifndef CFG_EXAMPLE_MSC_READONLY
    uint8_t* addr = msc_disk[lba] + offset;
    memcpy(addr, buffer, bufsize);
#else
    (void)lba;
    (void)offset;
    (void)buffer;
#endif

    return (int32_t) bufsize;
}

/*
 * Callback invoked when received an SCSI command not in built-in list below
 * - READ_CAPACITY10, READ_FORMAT_CAPACITY, INQUIRY, MODE_SENSE6, REQUEST_SENSE
 * - READ10 and WRITE10 has their own callbacks
 */
int32_t tud_msc_scsi_cb (uint8_t lun, uint8_t const scsi_cmd[16],
                         void* buffer, uint16_t bufsize)
{
    /* read10 & write10 has their own callback and MUST not be handled here */

    DEBUG("tinyUSB %s\n", __func__);

    void const* response = NULL;
    int32_t resplen = 0;

    /* most scsi handled is input */
    bool in_xfer = true;

    switch (scsi_cmd[0]) {
        default:
        /* Set Sense = Invalid Command Operation */
        tud_msc_set_sense(lun, SCSI_SENSE_ILLEGAL_REQUEST, 0x20, 0x00);

        /* negative means error -> tinyusb could stall and/or response with failed status */
        resplen = -1;
        break;
    }

    /* return resplen must not larger than bufsize */
    if (resplen > bufsize) {
        resplen = bufsize;
    }

    if (response && (resplen > 0)) {
        if (in_xfer) {
            memcpy(buffer, response, (size_t) resplen);
        }
        else {
            /* SCSI output */
        }
    }

    return (int32_t)resplen;
}

#endif
